Mutex and file access

Archived from groups: microsoft.public.win2000.file_system (More info?)

I hav ean application that writes to a file using fwrite() within a thread.
It also uses CreateMutex() and WaitForSingleObject() to control the access.
It would appear through logging that I am successfully creating the Mutex,
and successfully writing to the file. However, when the volume of activity
is high it will arbitrarily "lose" one of the lines of the file. It logs as
having written it, but it is not there.

I would appreciate any help or suggestions anyone can offer as this is
getting very frustrating to attempt to debug.

Thanks in advance